1. Field of the Invention
The present invention relates to an RFID chip package, and in particular, relates to an RFID chip package interposed between an RFID chip and an antenna and an RFID tag in an RFID (Radio Frequency Identification) system.
2. Description of the Related Art
In recent years, an RFID system has been put into practical use as an article information management system, which includes a reader/writer that generates an induction field; and an RFID tag that is attached to an article, and non-contact communication using an electromagnetic field is established between the reader/writer and the RFID tag to transmit predetermined information therebetween. Here, the RFID tag is composed of an RFID chip that has stored predetermined information therein and processes a predetermined RF signal; and an antenna that performs transmission/reception of RF signals.
Meanwhile, in the RFID system, since an RF signal is very weak, for example, a voltage booster circuit such as a multi-stage charge pump is provided in the RFID chip as described in Japanese Unexamined Patent Application Publication No. 2005-202943 and Japanese Unexamined Patent Application Publication No. 2009-130896, and the input/output impedance of the RFID chip is very high. Thus, in the antenna, it is necessary to match its input/output impedance to the input/output impedance of the RFID chip, and hence antenna designing is difficult, and in particular, size reduction and band expansion are difficult.